Michael Petruccelli says; Well it depends on a number of factors, including the cost of the house and type of mortgage you get. In general, you need to come up with enough money to cover three costs: earnest money- the deposit you make on the home when you submit your offer, to prove to the seller that you are serious about wanting to buy the house; the down payment. a percentage of the cost of the home that you must pay when you go to settlement; and closing costs, the cost associated with processing the paperwork to buy the house.